Nitrogen uptake kinetics of Prymnesium parvum (Haptophyte)

• The uptake rates of different nitrogen (N) forms (NO3-, urea, and the amino acids glycine and glutamicacid) by N-deficient, laboratory-grown cells of the mixotrophic haptophyte, Prymnesium parvum, weremeasured and the preference by the cells for the different forms determined. Cellular N uptake rates(rcell, fmol N cell-1 h-1) were measured using 15N-labeled N substrates. P. parvum showed highpreference for the tested amino acids, in particular glutamic acid, over urea and NO3 under the culturenutrient conditions. However, extrapolating these rates to Baltic Seawater summer conditions, P. parvumwould be expected to show higher uptake rates of NO3- and the amino acids relative to urea because ofthe difference in average concentrations of these substrates. A high uptake rate of glutamic acid at lowsubstrate concentrations suggests that this substrate is likely used through extracellular enzymes.Nitrate, urea and glycine, on the other hand, showed a non-saturating uptake over the tested substrateconcentration (1–40 mM-N for NO3- and urea, 0.5–10 mM-N for glycine), indicating slower membranetransportrates for these substrates

Ämnesord

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

Nyckelord

Amino acids 15N uptake Nitrogen uptake Prymnesium parvum Urea

Akvatisk ekologi

Aquatic Ecology

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